Turbine



D. C. DAVIS July 5, 1927.

TURBINE Filed Nov. 11. 1924 INVENTOR WITNESSES:

, 35 rupture due vto centrifugal force, unless an Patented July 5, 1927.

UNITED STATES 1,634,&97

PATIENT OFFICE.

DAVID C. DAVIS; 01? CHESTER, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEC- TRIO MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TURBINE.

Application filed November 11, 1924. Serial No. 749,300.

My invention relates to safety devices for high-speed rotors, especially the rotors of elastic-fluid,turbines, and has for its v0bjectto provideapparatus of the character designated which shall prevent motive fluid from being directed against the blading of the rotor should the speed of the rotor, for any reason, getbeyondcontrol of the governing or. regulating means usually provided therefor. g V

. vApparatus embodying, features of my 111- vention is illustrated in the accompanying I drawing in which Fig. 1 is a sectional view 'of a turbine having my improved safety device applied thereto; Fig. 2 is a View of a turbine rotor showing a method of attaching the blades thereto;v Figs. 3- and 4 illustrate modifications of. my invention. 7

In the patent to J. A. MacMurchy, No; 1,469,045, issued September 25, 1923, and as signed to the lVestinghouse Electric and Manufacturing Company, there is shown and described a safety device for a high-speed rotor of an elastic-fluid turbine, wherein at least/one of therotor blades has a weakened fastening adapted to give away upon the attainment of an excessive speed,-resulting. in

unbalancing the rotor, whereupon the unbalanced rotor rubsagainst a closelyfadjacent stationary element establishing a braking actionfl i j It has been found .with such apparatus that while the braking action described in the patent aforesaid is obtained, and the turbineis slowed down preventing-its further attendant promptly closes 05 the supply of motive fluid to the turbine, considerable damage may yet be done due to rubbing ofv the parts.@ v :.v

I accordingly provide, in a turbine, an element-adapted toibe ruptured by a' loosened bladethereof upon the attainment of an excessive. speed, and effective to'prevent the incoming motive fluid fro-m being directed against the rotor. blades, "whereupon it ceases rotating altogether or atleastrotates ata greatly reduced speed, thus entirely preventing further damage.

Fig. 1, at 10, an elastic-fluid turbine embodying a casing 11, and a rotor 12. The rotor 12 has a row of blades 13 mounted thereon. Upon the attainment of an excessive speed of the rotor 12 ,the blades 18 thereof are usually the first to rupture and fly outwardly, due to centrifugalstresses. In order to insure that the blades will be the first'to rupture, it is preferable to have at least one of the blades provided with a weakened root fastening,vwhereby it is adapted to become loosened upon the attainment of an excessive. speed of the rotor. In Fig. 2, I show the. blades 13 secured to the rotor 12 by means of pins 14, and show certain of the blades secured with pins 16 smaller in' di ameter than the pins securing the other blades, said pins 16 being of such strength' that they are adapted to shear due to'centrifugal force upon the rotors attaining an excessive speed. however, that this method of securing the blades is for the purpose of illustration only and that any method known in the art'whereby at least one of the blades of a rotor may become loosened upon the-attainment of ex! cessive speed may be employed.

, Elastic fluid for drivingthe rotor is admitted to the'turbine from an inlet 17 from whence it passes through a nozzle 18 wherein it is expanded and directed against the blades 13 of the rotor causing it to rotate in a manner well known in the art. 7 v

In accordance with the method of carrying out my invention illustrated in F ig. 1, I provide the fluid inlet with a widened portion 18 havinga wall 19, said widened portion being secured to the turbine casing at. 20. The wall 19 overhangs and is close.

ly spaced with respect to thebla'ding 13'.

The wall 19 is of suilicient strength to. withstand the pressureof the incoming motive fluid but is adapted to be ruptured by a loosened blade of therotor. Thus, should the rotor l2fattain an excessive speed, one or more of the pins l6.shear permittingits associated blades tobecome loosened from the rotor whereupon it strikes and ruptures the wall 19 of the fluid inlet and the incoming motive fluid instead #of passing through the nozzle 18 is by-passed across the Referringnow to the drawing, Ishow in ed in Fig. 3,11 provide the'fluidinlet 17 It is to bev understood,

ill)

llis adapted to be broken oil by a loosened with a widened out portion 18 as before and an overhanging portion 19. Fitted into the widened portion 11.8, immediately above the binding 13, is a thimble of some brittle material ill which is held in place in the portion [8 by means of lugs and The thimble :31 is of adequate strength to withstand the pressure of the incoming motive lluid and Imrmally closes oil communication between the inlet 17 and the opposite side of the turbine rotor 12 leading to the we haust. In this instance tl're overhanging portion 19 is secured to the casing, 11 by a Web member 24;. "[inipparzrtus made in accord anee with this modification, a loosened blade strikes the th-irnble 2.1., breaking itand permitting the iinatnniim motive fluid to bypass to the exhaust as before. The thilnble ill may then be replaced at slight expense and with but little work.

In accordance with Fig. 4, I show means pressure existing in the inlet 17. The piston 27 is normally held in its extreme right hand rmsition, "with the valve 26 opem by a spring 31 which is of sutlicient strength to nor mally hold the piston 27 to the position shown with pressures equalized on eachsiue thereof. At is shown a hollow plug or other suitable hollow closure member which overhangs the binding 13 and is screwetl or otherwise attached to the cylinder 28 closing the left hand end thereof; The member blade as heretofore described, whereupon the motive fluid escapes from the left hand end of the cylinder 8 the incoming motive fluid in the inlet '1' 21', moves it to the left and closes the valve 26, entirely shutting oil' the supply oi?n1olive fluid lo the turbine.

From the foregoing, it will be adparcnt that I have invented an improved satiety do vice for turbines elllbtKlVing means made elfective by a loosened blade oi the turoiue rotor to. n'event themotive fluid from being directed against the rotor blades.

\Vhile I have shown my invention in three forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof. am'lI desire. therefore that only such. l mitations shall be placed thereupon as are imposed by the prior art i' acting against the piston rotor, and means made ell'ective bya looslorth in the up eneitl blade for rendering the incoming lIl0- tive fluid ineil'ecti've for drivin the rotor but permittingsaid motive fluid. to pass through the turbine. p

in a turbine, a rotor, a "row of blades mien-ted ("in the ro'trn and being adapted to become loosened upon the attainment of an excessivespced, means for admitting motive lluid to the turbine and directing it against the inter; and means made effective by a looecned blade for diverting the motive illuid away from the blade row but permitting said motive fluid to pass through the tarbine.

lfin a turbine a rotor, a r w of blades mounted on the rotor.- and having at "least one blade so secured that it becomes loos ened upon the attainment of an excessive speed, a nozzle for expanding and directr a motive fluid against the row of News and having a fluid inlet leading mereto, and an element associated with the nozzle and adapted to be ruptured by a lioiisened blaue and elfective upon rupture to prevent the lnotiveflnid from being directed againsttne blades.

l. 1n a turbine, a rotor, a row of blades mounted on the rotor and having at lostone blade so secured that it lxsmrnes loosencd upon the attainment of an excessive speed, a nozxle tor expanding and direct-rug motive fluid againstthe row of blades and having at fluid inlet ltlldlflll thereto, av relatively thin wall for the fluid inlet overhanging the rotor and adapted to b61111 tured by a loosened bladei whereby the in coming fluid diverted away rrom the rotor.

In a turbine, mounted on the rotor and having at least oneblade so secured that it becomesloosened upon the attainment of an excessive sliieedra nozzle for expanitlnm and directing; motive fluid against the row of blades and having aflfluid inlet leading there-to; 'aa'ela tivelv thin wall for t-he fluid inlet over-- hanging the rotor dividing the fluid inlet from the exhaust and adapted to be ruptured by a loo ned blade, whereby the in coming motive fluid is bypassed to the exhaust. i

G. In a turbine, havinga rotor with blad ingmounted thereon. at least one of said blades being: so secured that its fastening gives way and the blade becomes detached upon the attainment of an excessive speed,

arotor a row of blades a nozzle for directing the motive fluid agalnst the row of bla es, and means associated With the nozzle adapted to be ruptured by a loosened blade, whereupon said means are eflective'for by-passing the motive fluid to the exhaust. N

7. In a turbine, a rotor, a row. of blades mounted upon the rotor, a nozzle for expanding and directing motive fluid against 10 the rotor blades and having a fluid inlet leading thereto, and an element carried by the nozzle and adaptedto be ruptured by contact with a rotor part and effective upon rupture to prevent the motive fluid from being directed against the blades.

In testimony whereof, I have hereunto subscribed my name this 21st day of Oct, 1924.

DAVID C. DAVIS 

